This invention relates to a catalytic combustor for generating steam downhole in an oil reservoir. By "downhole" it is meant that the steam is generated at or near the bottom of an oil well. The steam is injected into the reservoir to displace heavy oil. Steam injected this way forces oil out of the reservoir and into other wells located nearby. In the first attempts to do this, the steam was generated at ground level and fed to the reservoir through a pipe that extended down the oil well to the reservoir. This method is limited to depths of 3000 feet or less because too much of the steam condenses during the long passage down the well to the reservoir. One subject of Project Deep Steam, sponsored by the U.S. Department of Energy, is to develop a downhole steam generator.
Two types of downhole combustor are being developed. The first is a low pressure combustor wherein the heat from combustion is transferred to boiling water through the metal wall of a heat exchanger. The combustion gas is vented to ground level. This is the low pressure combustor because the combustion takes place at pressures not far above atmospheric. Only the steam is at the high pressure necessary to force the steam into the reservoir. In the high pressure combustor, a mixture of steam and combustion gas is formed by vaporizing water directly into the hot combustion gas. The combustion takes place at the high pressure necessary to force the mixture into the reservoir. The present invention relates to low pressure combustors.
One example of a downhole catalytic combustor is found in my copending U.S. patent application, Ser. No. 208,674, filed Nov. 20, 1980, entitled "Downhole Steam Generating Process." Another example of the use of catalytic combustion is found in my copending U.S. patent application, Ser. No. 145,597, filed May 1, 1980, entitled "Catalytic Heater."